1261032509 has 4 divisors (see below), whose sum is σ = 1375671840. Its totient is φ = 1146393180.

The previous prime is 1261032503. The next prime is 1261032517. The reversal of 1261032509 is 9052301621.

It is a semiprime because it is the product of two primes, and also a Blum integer, because the two primes are equal to 3 mod 4.

It is a cyclic number.

It is a de Polignac number, because none of the positive numbers 2^k-1261032509 is a prime.

It is a Duffinian number.

It is a congruent number.

It is not an unprimeable number, because it can be changed into a prime (1261032503) by changing a digit.

It is a polite number, since it can be written in 3 ways as a sum of consecutive naturals, for example, 57319649 + ... + 57319670.

It is an arithmetic number, because the mean of its divisors is an integer number (343917960).

Almost surely, 2^1261032509 is an apocalyptic number.

It is an amenable number.

1261032509 is a deficient number, since it is larger than the sum of its proper divisors (114639331).

1261032509 is a wasteful number, since it uses less digits than its factorization.

1261032509 is an evil number, because the sum of its binary digits is even.

The sum of its prime factors is 114639330.

The product of its (nonzero) digits is 3240, while the sum is 29.

The square root of 1261032509 is about 35511.0195432347. The cubic root of 1261032509 is about 1080.3772427569.

The spelling of 1261032509 in words is "one billion, two hundred sixty-one million, thirty-two thousand, five hundred nine".